Drive mechanism, particularly for picking system for looms



April 2 1963 H. scHMlD- 3,083,739

DRIVE MECHANISM, PARTICULARLY FOR PICKING SYSTEM FOR LOOMS Filed Aug. 23, 1961 5 Sheets-Sheet 1 Y NVENTOR. Hmlucb Scl-m3] www um A TTORNE Y April 2, 1963 H. CHMID DRIVE MECHANISM, PARTICULARLY FOR- PICKING SYSTEM FOR LOOMS 3 Sheets-Sheet 2 Filed Aug. 23, 1961 INVENTOR. Hewmcl SeimiJ 4 BYZJW muy,

ATTORNEY H. SCHMID April 2, 1963 DRIVE MECHANISM, PARTICULARLY FOR PICKING SYSTEM FOR LOOMS Filed Aug. 23, 1951 5 Sheets-Shea#l 3 l lll/4.

INVENTOR. 5M/dv Selma! BY w. Lam., 62W ATYKORNEY itd s aient Free BREVE MECHANSh/i, PARTiCULARLY EUR PECKEN'G SYSEEM EUR LGSP/11S Heinrich Schmid, Meilen, Sit/itzeriand, assigner to Firma Heinrich Schmid, Rapperswii, Switzerland Fied Aug. 23, 19M, Ser. No. 133,436 Claims priority, appiieation Switzerland Aug.. 26, 1960 2d tliaims. (Ci. i3i-ld7} The present invention relates to a novel drive mechanism and, more particularly, to a drive mechanism adapted for use in conjunction with a loom picking system of the type having a cam member or eccentric for effecting the picking stroke.

There are already known to the art loom picking systems wherein the eccentric or cam eifecting the pick stroke has imparted at the moment of said pick stroke an additional angular velocity with respect to its driving shaft. This acceleration of the cam has proven to be a suitable method of increasing the force of the pick.

In the heretofore known picking systems of the aforementioned type, the energy for carrying out the pick is primarily taken from the driving shaft. In View of the fact that this energy is relatively high, the driving shaft is subject to certain torsional effects, which may in certain circumstances delay or retard the pick, thereby resultiig in irregularities in the fabric. Moreover, the known picking systems of this type also require a` relatively complex mechanism, so that the subsequent incorporation or adaptation of such systems in existing looms is oftentimes extremely difcult or even impossible.

The picking system designed according to the teachings of the present invention and of the type wherein -a cam or eccentric is seated in a freely rotatable manner on the driving shaft, is characterized by the fact that the driving shaft carries gripper or catch means which engages the cam between the individual picks so as to impart to said cam the speed of the driving shaft. Further, tne driving shaft carries a collar or sleeve member driven at a higher rotational speed than said driving shaft, and wherein a coupling member is provided which connects the sleeve to the cam during each pick. Moreover, the cam is provided with a control surface cooperable with an axially movable slide member connected to the body of the `weaving loom adapted for engaging and disengaging the coupling member.

With such an arrangement of the picking system, it is now readily possible to take the required energy for the picking operation transmitted from the sleeve to the cam from a driving unit which is separate from that of the weaving loom. It is, however, also possible to connect the sleeve through an intermediate shaft to the driving unit of the weaving loom, so that the energy for the pick is transmitted through the intermediary of a `shaft which is separate from an eccentric shaft. According to a preferred embodiment of the present invention, the arrangement of the drive system for the pick is such `as to permit the coupling to be rendered inoperative by means of a control bar of the loom, said control bar also being designed to disengage the main driving motor of the weaving loom in a known manner. Owing to the fact that the transmission of the picking energy to the eccentric is separated from the driving shaft, said driving shaft responsible for initiating or tripping the pick is not subjected to any torsional stresses which would cause a deformation of said shaft, and thereby result in irregularities in the woven fabric.

It is a rst important object of the present invention to provide a drive system which eliminates the disadvantages of the heretofore known picking systems.

Another important object of the present invention is to provide a novel drive mechanism adapted for use in loom picking systems which is capable of increasing the force of the pick in a positive and reliable manner. c

Still a further important object of the pres-ent invention is to provide novel drive means for a loom picking system which is relatively simple in construction and which may be easily adapted to existing loom structures.

Yet a further important object of the pres-ent invention is to provide means for imparting increased rotational speed to a rotatable eccentric during the pick stroke of a loom in order to enhance the force of the pick.

These and still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific example, while indicating a preferred embodiment of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

In the drawings:

FIG. 1 is a longitudinal sectional view taken through a first embodiment of the drive mechanism of the present invention.

FIG. 2 illustrates an end view of the device taken in the direction of arrow Ain FG. l.

FIG. 3 is a cross-sectional view taken along the line lll-HI in FIG. l.

FlG. 4 shows an end view of the device taken in the direction of the arrow B in FIG. l; and

FIG. 5 illustrates a second embodiment of the present invention taken in longitudinal section.

Referring now to the drawings wherein only enough of the loom structure has been shown to provide a clear `understanding of the invention and in particular to FIGS. 1 and 2, it is to be seen that a gripper or catch plate 2 provided with a pair of lateral projections or legs 3 and 3 (see FIG. 2) is keyed or otherwise rigidly connected to the main driving shaft l, which shaft is capable of being connected to the main driving motor of the weaving loom by suitable engaging or coupling means known to the art and not shown in the drawing. Rotatably mounted on the driving shaft 1 is a picking eccentric member or cam 5 provided with a dog member i which is capable of abutting against the projection 3 of the catch plate Z to thus be operably connected in rotational relation with the latter. The dog member 4 is urged into contact with the projection 3 by a torsion spring 27 or the like connected at one end via a pin in to the dog member d. of the picking eccentric 5 and at the other end via a pin 2a to the catch plate 2. The picking eccentric 5 is, however, capable of performing a limited movement relative to the catch plate 2 and in opposition to the torsion spring 27. The driving shaft 1 is rotatably mounted in a bearing 6 arranged in a bore 37 provided in the loom lframe 25, said bearing being maintained locked in its aXial position by a collar member 7. As clearly shown in FIG. 4 the ybearing 6 is provided at one end with a rectangular ange 38 provided with a pair of recesses or slots 39 through which the respective securing screws 4e extend. This arrangement provides the bearing 6 with a certain limited play or degree of freedom of movement for radial turning or displacement, as shown in phantom in FIG. 4, a facility which is necessary for reasons which will be explained more fully hereinafter.

Concentrically arranged on the bearing 6, as best seen in PIG. 1, is a bushing member 8 which is capable of sliding axially or longitudinally. This arrangement including a slide member 9 is intended to prevent the bushing 8 from rotating relative to the bearing 6, said slide member 9 slidably engaging a keyway l() of the bearing 6 and being rigidly connected to the bushing S, for example, by means of a set screw or locking pin 11.

Rotatably mounted on the bushing 8 is a main sprocket wheel 12 which is -driven independently of the driving shaft 1 by a yseparate drive motor 15 acting through the intermediary of the -driving shaft `14. The `main sprocket wheel 12 and a minor sprocket wheel 16 carry an endless driving chain 13. In order to change the transmission ratio, the minor sprocket wheel 16 can be replaced with a wheel of different size. tional speed of the sprocket wheel 12 must always be greater thanV that of the picking eccentric 5, at least when such elementsare in disengaged position, and the direction of rotation of these two elements must always be the same. The operationof the motor 15 which drives the minor sprocket wheel 16 may be advantageously coupled with the main driving motor of the weaving loom, not shown in the drawing.

The bushing 3, which is capable of sliding axially or longitudinally with respect to the bearing 6, is provided at its end facing the picking eccentric 5 with a roller element 19 (see FIG. 3), preferably designed as a radial antifriction bearing, and which bears against the end face 2) of the picking cam or eccentric 5. As will be seen by inspecting FlGURE 1 the roller element 19, in the desired construction shown, is-forrned of two roller bearings 19a, 19b which are rotatably seated upon a common support pin 19C and are situated adjacent the inner and outer wall portions -ofbushing 8. The main sprocket wheel 12, rotatably mounted on the bushing 3 is provided with :a shoulder or projection 41 abutting against the roller 19. This arrangement further includes a resilient member, such as the compression spring 21, which rests at one end in a bore 22 provided for the sprocket wheel 12 and at the other end against a retaining ring 23. By virtue of ythe provision of this compression spring 21, the main lsprocket wheel 12 is subjected to an axial pressure in the direction of the picking eccentric 5, said pressure being transmittedthrough the recessed projection or shoulder 41 to the roller element 19 ofthe bushing 8, thereby forcing the roller element 19 against the end face 20 of the picking eccentric 5. The retaining ring 23 is supported by the loom body or frame 25 through the intermediary of an adjacently arranged, axial antifriction bearing 24.

To ensure that the retaining ring 23 is entrained by the rotation Vof'the main sprocket wheel 12, there is provided a pin 34 mounted in suitably arranged bores 35 and 36 provided in the retaining ring 23 and the main sprocket wheel 12, respectively, thereby positively interconnecting these elements. The pin 34 is arranged so as to be free to slide axially in the bore 35 inl order to permit a degree of-reiative axial displacement of the main sprocket wheel 12 with respect to the retaining ring 23.

As clearly shown in FIG. 3, the end face 20 of the picking eccentric 5 isprovided in the region of the contact area of the roller element 19 with a cam surface or control groove 26 whichthe roller element 19 can enter under the iniiuence of the compression spring 21. Thus, there results a controlled laxial r longitudinal displacement to a-desired extent of the bushing 8 and the main sprocket wheel 12 relative to the picking cam member or eccentric 5.

As best seen in FIGS. 1 and 3, the opposed faces or sides of the main sprocket wheel `12 and the picking cam member or eccentric are provided with engageable coupling claws 17 and 18, respectively. Thus when the control groove 26V and the roller 19 enable the main sprocket wheel 12 to move towards the picking eccentric 5, these coupling claws 17 and 18 interengage with one another and establish a driving connection between these two members. As a result, the picking eccentric 5 is caused to briefly rotate in synchronism with the main sprocket wheel 12 and at the speed of drive motor 15. AWhen the roller 19 moves out of the control groove 26,

Whatever the case, the rota-V 4 such engaging connection of the claws 17 and 18 is interrupted.

The driving sprocket chain 13 is provided with a certain clearance for the major sprocket wheel 12 and the minor sprocket wheel 1e in order to avoid jamming when axial displacement of the two sprocket wheels 12, 16 relative to one another occurs.

The teeth of the main sprocket wheel 12 may also be formed as a separate part capable of sliding axially on the main sprocket wheel 12, while nevertheless in positive rotatable connection therewith. To this end, the mutually contacting surfaces of the rim of the .tooth Segment andthe body of the sprocket wheel 12 may be provided with interacting keys and keyways in a known manner. In such construction, the toothing rim is preferably rigidly connected to the retaining ring 23. As a result of such an arrangement, the driving chain 13 does not follow the axial displacement of the main sprocket wheel 12 relative to the minor sprocket wheel 1-5 and, therefore cannot become jammed.

The picking eccentric 5 is connected in a conventional manner to a rod or linkage assembly 28, which transmits the stroke through an intermediate member 29' to a picking stick 39, which strikes they weaving shuttle at regular intervals. The rod assembly 28 is designed in thefform of a two-armed lever which is pivotally mounted at point 31 and carries a cam follower or roller 42 rolling in contact with the surface of the picking eccentric or cam member 5. The picking stick 30 is provided in a known manner with a shoe member 43 which rolls or rocks in contact with an oscillating support 44, and which oscillates about the hinging axis of the batteri in synchronism therewith.

In order to maintain the sprocket wheel 12 in disengagement from the picking eccentric 5, the arrangement Y of the present invention includes a locking wedge member 32 adapted to be wedged between the nose portion 45 of the slide member 9 and the flange 38 of the bearing 6 (see FIG. 4) defining a locking recess 32a with the result that the bushing 8 and, with it, the main Sprocket Wheel 12 are prevented from moving axially in the direction of the cam member 5.

To operate the locking wedge 32, the arrangement preferably provides a control bar (not shown) which in conjunction with a rod assembly, of which a lever number is designated at 46 in FIG. 4, permits the locking wedge 32 to be moved in and out of the locking or wedgereceiving recess 32a. The function of moving fthe lockingwedge 32 in and out of said wedge receiving recess is preferably combined with that of engaging and disengaging the driving vshaft 1. The aforementioned control bar may `be advantageously designed to cause coupling of the drive shaft 1 with its main loom drive motor as well as actuation of the locking wedge 32 in a manner readily apparent to those` skilled in the art.

With the aforedescribed arrangement the operation of the picking system proceeds as follows:

Operation `of a common switch turns on the main driving motor of the weaving loom as well as the drive motor 1S, at which stage the driving shaft 1 is stiil disengaged and the main sprocket wheel 12 runs idle on said shaft. Operation of the control bar via suitable linkage means or otherwise known to the `art couples @the driving shaft 1 with the main loom driving motor and also retracts the locking wedge 32 yfrom its receiving recess 32a. The rotation of the driving'shaft 1 is transmitted through the catch plate 2 rigidly connected therewith and via the leg or projection 3 'and the dog member 4 bearing against said projection tothe picking cam or eccentric 5, which eccentric member is `thus caused to rotate at `the same speed as the driving shaft 1. The main sprocket wheel 12 driven via drive motor 15, the driving shaft 14, the minor sprocket 16 and the chain 13, rotates `on lthe bushing d serving yas a journal in the same direction as the picking eccentric 5. The only difference, however, is that the speed of the main sprocket wheel 12 is higher than that of the picking eccentric 5. The compression spring 21 resting against the retaining ring 23 exerts a pressure upon the main sprocket Wheel 12 in the direction ofthe picking eccentric 5, said pressure being transmitted through the shoulder or projection 41 to the rolier element 19 of the bushing S and thus pushing the latter against the face 2t) of the picking eccentric 5. When the picking eccentric 5 assumes a certain predetermined angular position relative to the axially movable roller element 19, the latter enters the cam surface or control groove 26, with the result that the bushing 8 and the main sprocket wheel 12, under the action lof the compression spring 21, move towards the picking eccentric 5 with the engageable coupling claws 17 and 1li now engaging with each other. As a result, the picking eccentric S is entrained and accelerated by the main sprocket wheel 12, which is rotating at a higher speed. than the cani or eccentric 5. At this stage of the operation of the device, the dog d disengages from the projection 3 of the catch plate 2 in opposition to the torsion spring .27. During this brief, accelerated movement of the picking eccentric 5 there is imparted to the weaving shuttle a blow or force by means `of the roller 42, the rod assembly 28, the intermediate member 29 and the picking stick 30. To permit an accurate setting of the startingpointof the 'accelerated movement of the picking eccentric 5 with respect to the position of the cam yfollower or roller 4Z, provision is made as af-oredcscribed for a certain .radial adjustment of the bearing 6 and, with it, the bushing S. As a result, i-t is possible to ladjust the position of the roller element 19 with respect to 'the cam surface of the control groove 26. The radial adjustment of the bearing 6 is rendered possible by means of the slotted `holes T39. Directly after the transmission of the Iforce or pick blow, the roller element 19 leaves the deepened or recessed portion 26a of the control gr-oove 26, as is clearly shown in FlG. 3. The bushing 8 and the main sprocket wheel 12 return `against the action of the compression spring 21 to their initial position, and the driving connection between the main sprocket wheel 12 and the picking eccentric 5 is interrupted. Thus released, the picking eccentric 5 is returned to its initial position by the torsion spring 27, with the result rthat the dog member 4 again comes to rest against the projection 3, and the picking eccentric 5 again runs in synchronism with the driving shaft 1. The other projection 3" provided for the catch plate 2 serves to limit the rotation-al displacement of the picking eccentric 5 with respect to fthe catch plate 2 upon disengagement of said picking eccentric 5 from the main sprocket wheel 12. Such limiting effect of the rotational displacement of said eccentric is due to the fact that the dog member 4 bears against said projection 3' 'and is subsequently returned to its initial position by the resetting spring 27. It is to be noted that the aforedescribed operational cycle repeats itself each time the roller 19 enters the control groove 26.

To stop the action of the hatten and the shuttle,ioperation of the aforedescribed control bar and the associated rod assembly, of which a lever is shown at 46 in FIG. 4, causes the locking wedge 32 to move into the recess 32a dened by the nose 45 of the slide 9 and the flange 38 of the bearing 6. As a result, both the bushing S and the main sprocket wheel 12 are prevented from executing any axial displacement, While simultaneously the driving shaft 1 is disengaged from its main drive motor. As a consequence thereof, the main sprocket Wheel 12 driven by the separate motor merely runs idle on the shaft 1. The embodiment shown in FIG. 5 differs from that shown in FIGS. l to 4 primarily insofar as the pickcontrolling groove 26 is arranged on the catch plate 2' corresponding to the catch plate 2 shown in FIG. l. The control groove or cam surface 26' is preferably arranged on the peripheral surface of said catch plate 2. This groove is engaged by a transmission arm 50 by means of the ball bearing 51 secured to its free end, said transmission arm S0 lbeing pivotably connected at its other end to a yoke 52 secured to the loom body 25. Also pivotably connected to the yoke S2 is a lever 53 which is connected at its opposite end to a ring member 54. This ring member 54 is freely mounted on a coupling ring 5S provided with an upwardly extending flange 55a having coupling claws 17. The coupling ring 55 is slidably mounted on the main sprocket wheel 12 and is in rotatable connection therewith. The ring member v54 rests upon and in engagement with the coupling ring 55 through the intermediary of an axial -antifriction bear-ing 56, and engages on its opposite side a bearing 57 which, in turn, bears against the main sprocket Wheel 12. This sprocket wheel which is rotatably mounted (on the shaft 1, bears via a thrust ball bearing 58 against the loom body 2S.

The pivotal lever 53 is connected to the transmission arm 50 by means of a rod member 59 and a spacer tube 6i) slipped onto said rod 59. The arrangement is such that said rod member 59 extends piei'cingly through said transmission arm Sti and, by means of a compression spring 61 of adjustable pre-tension, urges said transmission arm 5d against the spacer tube 60.

The movement of the transmission arm 50 during the rotation of the catch means 2 and the control groove 26' is transmitted through the spring 61 to the pivotable lever 53 which tends to move the ring 54 and the coupling ring 55 into its claw engaging position, for the purpose of engaging the claw couplings 17', 1S. When the claw portions of the claw coupling sections 17' and 18 engage with one another, the spring 61 is stressed, with the result that the pivotable lever 53 moves the coupling ring 55 into its coupling position so that the claws of one coupling section directly engage with the corresponding recesses of the other coupling section.

To prevent the coupling claws from engaging or, rather, to stop the picking motion, there is connected to the pivotable lever 53 a rod 62 which extends through a suitably provided recess in the loom body 25 and is engaged beneath its head by the wedge member 32. When assuming one of its end-positions, the wedge 32' contacts the free end of rod 62 and thus prohibits any inward displacement of the rod 62, and thereby pivoting of lever 53 to prevent engagement of the coupling claws, in an analogous manner as with the first described embodiment.

Accordingly, during each revolution of the catch plate 2',

pivoting of the transmission arm 50 is absorbed by the spring 61. Instead of the torsion spring 27 arranged between picking eccentric 5 and catch plate 2, as employed with the embodiment shown in FIGS. l to 4, the embodiment shown in FIG. 5 is provided with a braking band 63 which encompasses the picking eccentric or cam member S and directly brakes the movement thereof, as soon as the coupling is disengaged. For the remainder of the mode of operation of this embodiment such is the same as that previously described with respect to the description of operation accompanying FIGS. `l-4, so that further details can be dispensed with.

Having thus described the present invention what is desired to be secured by United States Letters Patent, is:

l. In a drive mechanism, a drive shaft adapted to be rotated, catch plate means rigidly secured. to said drive shaft, a cam member mounted freely rotatable on said drive shaft including means for engaging said cam member in driving relation with said catch plate means, drive means for imparting rotational movement to said cani member at greater rotational speed than said drive shaft, and means cooperating with said cam member for selectively engaging said cam member with said catch plate means and said drive means.

2. In a drive mechanism adapted for increasing the pick force in a loom; a drive shaft adapted to be rotated, catch plate means rigidly secured to said drive shaft, a cam sheaves `member mounted freely rotatable on said drive shaft pro- -videdrwith coupling means for engaging said cam member in driving relation with said catch plate means, drive cam member mounted freely rotatable on said drive shaft provided with coupling means for engaging said cam member in driving relation with said catch plate means, drive means including a gearing mechanism for imparting rotational movement to said cam member at greater rotational speeds than the rotational speed of said drive shaft, and means cooperating with said cam member for selectively engaging said cam member with said catch plate means and with said gearing mechanism of said drive means, respectively, whereby the rotational speed of said cam member can be selectively changed in accordance with the operational steps of the loom.

4. `ln a drive mechanism for increasing the pick force in a loom according to claim` 3; wherein said gearing -mechanism includes a pair of spaced sprocket wheels drvingly interconnected by an endless sprocket chain,

one of said sprocket wheels being mounted for relative axial and rotational movement with respect to said drive shaft.

5. In a drive mechanism adapted for increasing the pick force in a loom; a drive shaft adapted to be rotated, catch plate means rigidly secured to said drive shaft, a cam member mounted freely rotatable on said drive shaft provided with coupling means for engaging said cam member in driving relation with said catch plate means, drive means for imparting rotational movement `to said cam member at greater rotational speeds than the rotational speed of said drive shaft, and means cooperating with said cam member including a displaceable slide for selectively engaging said cam member with said catch plate means and with said drive means, respectively, whereby the rotational speed of said cam member can be selectively changed in accordance with the operational steps of the loom.

6. :ln a drive mechanism adapted for increasing the pick force in a loom; a drive shaft adapted to be rotated, catch plate means rigidly secured to said drive shaft, a cam member mounted freely rotatable on said drive shaft provided with coupling means for engaging said cam member in driving relation with said catch plate means, a follow member in registry with said cam member adapted to increase the force of the pick of the loom, drive means for imparting rotational movement to said cam member at greater rotational speeds than the rotational speed of said drive shaft, and means cooperating with said cam member for selectively engaging said cam member with said catch plate means and with said drive means, respectively, whereby the rotational speed of said cam member can be selectively changed in accordance with the operational steps of the loom.

7. In a drive mechanism adapted for increasing the 'pick force in a loom; a drive shaft adapted to be rotated,

catch plate means rigidly secured to said drive shaft, a

cam member mounted freely rotatable on said drive shaft provided with coupling means for engaging said cam member in driving relation with said catch plate means,

drive means including an axial displaceable sprocket wheel mounted for relative rotational movement on said drive shaft for imparting rotational movement to said cam member at greater rotational speeds than the rotational speed of said drive shaft, and means cooperating with said cam member for selectively engaging said cam member with said catch plate means and with said drive means, respectively, whereby the rotational speed of said cam member can be selectively changed in accordance with the operational steps of the loom, said cooperating means inciuding means for urging said sprocket wheel into engagement with said cam member during the pick stroke of the loom.

S. In a drive mechanism adapted for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft; a drive shaft adapted to be rotated, catch plate means rigidly secured to said drive shaft, a cam member mounted freely rotatable on said drive shaft including meansY for engaging said cam member with said catch plate means between picking intervals, driven means carried by said drive shaft rotatable relative thereto and adapted to drivingly engage said cam member, a drive motor for driving said driven meansand said cam member at a greater rotational speed than the speed of said drive shaft when engaged by said driven means, and means cooperating with said driven means to axially displace the latter in the direction of said cam member for selectively engaging said cam member with said drive motor, whereby the rotational speed of said cam member can be increased during the pick stroke of the loom to increase the force of the pick.

9. In a drive mechanism adapted for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft; a drive shaft adapted to be rotated, catch plate means rigidly secured to said drive shaft, a cam member mounted freely rotatable on said drive shaft provided with means for engaging said cam member with said catch plate means between picking intervals, driven means carried by said drive shaft rotatable relative thereto and adapted to be axially displaced so as Yto drivingly engage said cam member, a drive motor for `driving said driven means and said cam member at a greater rotational speed than the speed of said drive shaft when engaged by said driven means, and means cooperatling with said driven means to axially displaceV the same Vfor selectively engaging said cam member with said drive `of said cam member to couple said driven means with said cam member.

10. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 9; including spring means biasing said driven means in the direction of said cam member.

11. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to 'claim 9; wherein said driven means includes a sprocket wheel axially slidable on said drive shaft.

l2. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 9; wherein said means adapted to be displaced is a slide member axially displaceable relative to said drive shaft.

13. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim l2; wherein bearing means carried by said drive shaft movably support said slide member, said bearing meansincluding means permitting adjustment of said slide member angularly about said drive shaft.

14. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 12; wherein said cam member is provided with a control surface, rollerV means carried by said slide member movable into contact with said control surface to permit engagement of said driven means with said cam member.

15. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 9; wherein said means adapted to be displaced is a pivotable lever cooperating with said driven means.

16, In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 15; wherein said catch plate means is provided with a control surface, said cooperating means including linkage means communicating said control surface with said pivotable lever.

17. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 9; including Wedge means cooperable in one position with said cooperating means to prevent engagement of said driven means with said cam member.

18. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 9; wherein said driven means is a collar provided with a toothed rim, said toothed rim being mounted on said co1- lar for axially slidable movement with respect thereto while simultaneously rotatable therewith.

19. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 9; wherein said catch plate means includes two projecting legs, said cam member being provided with a dog member engageable with at least one of said projecting legs to couple said catch plate means with said cani member, and resilient means for urging said dog member into contact with said one projecting leg when said driven means and said cam member are in non-engaging position.

20. In a drive mechanism for increasing the pick force in a loom by increasing the angular velocity of a cam member relative to its drive shaft according to claim 9; wherein said driven means and said cam member are provided with intergripping means defining a claw coupling, said driven means including a toothed sprocket portion and a driving chain for said sprocket portion.

References Cited in the le of this patent UNITED STATES PATENTS 1,164,094 Hutchins et al Dec. 14, 1915 1,966,704 Bell et al. July 17, 1934 2,517,454 Alstyne Aug. 1, 1950 2,552,246 Wilckens May 8, 1951 2,760,522 Higgins Aug. 28, 1956 

1. IN A DRIVE MECHANISM, A DRIVE SHAFT ADAPTED TO BE ROTATED, CATCH PLATE MEANS RIGIDLY SECURED TO SAID DRIVE SHAFT, A CAM MEMBER MOUNTED FREELY ROTATABLE ON SAID DRIVE SHAFT INCLUDING MEANS FOR ENGAGING SAID CAM MEMBER IN DRIVING RELATION WITH SAID CATCH PLATE MEANS, DRIVE MEANS FOR IMPARTING ROTATIONAL MOVEMENT TO SAID CAM MEMBER AT GREATER ROTATIONAL SPEED THAN SAID DRIVE SHAFT, AND MEANS COOPERATING WITH SAID CAM MEMBER FOR SELEC- 